There has been a method for determining impersonation based on a distance difference from a camera in a face area or a distance difference to a background.
However, in the conventional technology described above, when there is an area where a distance from a camera fails to be acquired, a value of the area where the distance fails to be acquired is forcedly calculated, and a performance for detecting impersonation is deteriorated. When an action such as simple interpolation is taken, simple impersonation using cutting of a photograph, folding, and the like is hardly detected.